I purchased a single handle shower only faucet # 873-4704. What I need is a tub and shower faucet # 873-4604. Is there any way to convert the shower only valve to a tub and shower valve without cutting into the tiled wall?

No conversion I know of. The tub/shower faucet you should have bought has a diverter, to get that you have to buy the complete 873-4604. Also no way to install a 4604 without cutting into the wall unless you have a wall in the next room behind the mixer that you can open up.